diff -r b72c6db6890b -r 5dc02b23752f src/gui/text/qtextdocument.h
--- a/src/gui/text/qtextdocument.h	Wed Jun 23 19:07:03 2010 +0300
+++ b/src/gui/text/qtextdocument.h	Tue Jul 06 15:10:48 2010 +0300
@@ -256,6 +256,13 @@
     void undo(QTextCursor *cursor);
     void redo(QTextCursor *cursor);
 
+    enum Stacks {
+        UndoStack = 0x01,
+        RedoStack = 0x02,
+        UndoAndRedoStacks = UndoStack | RedoStack
+    };
+    void clearUndoRedoStacks(Stacks historyToClear = UndoAndRedoStacks);
+
     int maximumBlockCount() const;
     void setMaximumBlockCount(int maximum);